TORONTO -- North American stock markets were mixed while the Canadian dollar fell for a sixth straight session Thursday amid continuing worries over whether Britain will exit the European Union.

The S&P/TSX composite index in Toronto closed down 41.04 points at 13,882.41, with the mining and energy sectors among the biggest weights.

In commodities, the July contract for North American benchmark crude oil fell 1.80 to US$46.21 a barrel, while the August contract, which is currently trading at a larger volume, was down $1.76 at US$46.74 a barrel.

The August contract for gold bullion, which is seen as a safe haven in times of turmoil, rose $10.10 to US$1,298.40 a troy ounce.

Elsewhere in commodities, July natural gas shed a penny to US$2.59 per mmBtu and July copper gave back four cents to US$2.05 a pound.

The loonie fell again, fading 0.21 of a U.S. cent to 77.15 cents US.

In New York, indexes broke a string of five consecutive losses, with the Dow Jones industrial average gaining 92.93 points to 17,733.10, while the broader S&P 500 added 6.49 points to 2,077.99 and the Nasdaq composite advanced 9.99 points to 4,844.92.

The gains came despite growing uncertainty over the outcome of a British referendum next week in which British voters will decide whether they want to leave the EU.

Current polls forecast that it will be a tight race, with the Bank of England cautioning that a so-called Brexit would likely result in damage to the economy and the pound dropping sharply.

"The real possibility is that it may happen and it makes markets worried about what will happen next," said Roland Chalupka, chief investment officer at Fiduciary Trust Canada.

He noted that there are serious concerns over British growth in the short term, which could stagnant with trade deals needing to be renegotiated over the next few years.

Also, multinational companies headquartered in Britain could look to move out of the country and London could potentially lose its reputation as a major financial capital, Chalupka said.

A yes vote could also prompt other countries to consider similar referendums of their own.

"The whole concept of the EU would face a lot more scrutiny and be far more uncertain if Britain does, in fact, decide to leave," said Chalupka.

In European trading, Germany's DAX fell 0.59 per cent, while France's CAC 40 was off 0.45 per cent and Britain's FTSE 100 was down 1.30 per cent.

In Asia, Tokyo's Nikkei 225 plunged 3.05 per cent after the Bank of Japan decided against further easing of monetary policy to help the country's faltering recovery. The Bank of Japan already is pumping about 80 trillion yen (US$769 billion) into the country's economy each year with purchases of Japanese government bonds and other assets.

With files from The Associated Press